The present invention relates to a flexible heating or cooling system for heating, or cooling, a contained item or product.
Various types of self-heating/self-cooling containers are known in the art for heating or cooling the contents held within the container to a desired temperature.
In one type of self-heating/self-cooling containers, the containers function solely as receptacles into which the final user may place any item they desire to heat/cool. Some of these receptacles are designed with a certain product in mind, such as a standard size can of food or beverage. For example, U.S. Pat. No. 2,425,900 describes a package that is readily transportable and adapted to receive any standard can suitable for the size of the package.
Several examples of flexible self-heating/self-cooling containers exist in the literature. The inventions disclosed in U.S. Pat. No. 5,465,707 uses an electrolytic-solvent to activate exothermic-chemical pad or powder. The exothermic-chemical pad is enclosed within an absorbent envelope and the electrolytic-solvent is contained within a bag. It also discloses a pouch for foodstuff. U.S. Pat. No. 5,465,707 discloses an invention that consists of a thermal insulated outer barrier layer in which is contained the exothermic-chemical pad, the electrolytic solvent containing bag, and the pouch for foodstuff. The solvent bag is affixed to a board material, which provides a rigid structure for the proper functioning of a tear filament pull-tab mechanism or a means for rupturing the solvent bag. To properly work, this package must have a specific orientation and cannot be moved about once activated because of the potential to spill the activating fluid, i.e., it is not self-contained.
U.S. Pat. No. 3,685,507 describes as one embodiment a multi-walled container unit fabricated of plastic film, which is comprised of three flexible bags of plastic film. An outer bag within which is suspended an inner bag of shorter length. The outer bag also has disposed in its bottom a charge of chemical and a small plastic bag, which has sealed therein a charge of a second chemical. The bulk of the heating element and thus the chemical reaction is located at the bottom of the package. This is undesirable because the heating element is not disposed adjacent and along the product to be heated or cooled. Because of this, it is suggested that the heating or cooling is inefficient. Also, the patents suggests that shaking or inverting the package would to disperse the contacted chemicals throughout the container and into the annular mixing space.
U.S. Pat. No. 4,838,242 describes a device for changing the temperature of material placed therein by a user. The device comprises an inner flexible cylindrical member having an open end for receiving and changing the temperature of an item such as a can of soda or food and a temperature changing element within the walls of the cylindrical member. However, this device does not permit the activation of the heating or cooling element while the item to be heated or cooled is within the cylindrical member without damaging the item, i.e., no offset activation point.
U.S. Pat. No. 5,263,991 describes a thermal packaging unit for heating a biocompatible implant that is self-contained in that the elements used for heating the biocompatible device are located within the thermal packaging unit. To provide means for heating the biocompatible implant, the thermal packaging unit includes a first compartment that is operable to contain calcium chloride, that defines a storage area for receiving the biocompatible implant, and a second compartment disposed within the first compartment that is operable to contain water. When the wall of the second compartment is ruptured, as by gently squeezing the thermal packaging unit, water from the second compartment is able to combine with the calcium chloride in the first compartment in an exothermic reaction. Again, this device does not include an offset activation point that will permit activation of the temperature changing element without damaging the item to be heated or cooled.
None of these patents address the issue of providing a solid-liquid-, or liquid liquid-interaction, or crystallization of a supercooled solid-based thermal regulation source in a flexible container while providing for an activation method that will prevent the accidental damage of the product contained within the package. Also, none of these patents address the problem of maintaining the integrity of the structure containing the reactive chemistry. Further, the system is characterized by providing optimal heat transfer by having the heat source adjacent to the item to be heated.
The present invention is directed to a flexible heating/cooling system comprising an enclosed package containing a product and at least two flexible temperature changing elements. Each flexible temperature changing elements comprises a first chamber and a second chamber disposed proximate to the first chamber. At least a portion of the at least two flexible temperature changing elements is disposed proximate to the product so that thermal energy from the at least two flexible temperature changing elements heats or cools the product.